1. Field of the Invention
The present invention relates to explosive compositions of the water-in-fuel emulsion type in which an aqueous oxidizer salt solution is dispersed as a discontinuous phase within a continuous phase of a liquid or liquefiable carbonaceous fuel.
2. Description of the Prior Art
Water-in-fuel emulsion explosives are now well known in the explosives art and have been demonstrated to be safe, economic and simple to manufacture and to yield excellent blasting results. Bluhm, in U.S. Pat. No. 3,447,978, disclosed an emulsion explosive composition comprising an aqueous discontinuous phase containing dissolved oxygen-supplying salts, a carbonaceous fuel continuous phase, an occluded gas and an emulsifier. Since Bluhm, further disclosures have described improvements and variations in water-in-fuel explosives compositions.
These include U.S. Pat. No. 3,674,578, Cattermole et al.; U.S. Pat. No. 3,770,522, Tomic; U.S. Pat. No. 3,715,247, Wade; U.S. Pat. No. 3,675,964, Wade; U.S. Pat. No. 4,110,134, Wade; U.S. Pat. No. 4,149,916, Wade; U.S. Pat. No. 4,149,917, Wade; U.S. Pat. No. 4,141,767, Sudweeks & Jessup; Canadian Patent No. 1,096,173, Binet & Seto; U.S. Pat. No. 4,111,727, Clay; U.S. Pat. No. 4,104,092, Mullay; U.S. Pat. No. 4,231,821, Sudweeks & Lawrence; U.S. Pat. No. 4,218,272, Brockington; U.S. Pat. No. 4,138,281, Olney & Wade; and U.S. Pat. No. 4,216,040, Sudweeks & Jessup. Starkenberg et al., in U.S. Pat. No. 4,545,829, describe a process for making an amatol explosive wherein an emulsion of ammonium nitrate in melted TNT is produced with emulsion is thereafter cast into shapes. Ekman et al., in U.S. Pat. No. 4,310,364, disclose a cap-sensitive, water-in-fuel emulsion in which the fuel phase consists primarily of aromatic nitro-compounds. However, the compositions of Ekman et al. have proven to be of limited commercial value because the emulsion formed is short-lived and highly crystallized and, hence, soon loses its stability and sensitivity, particularly at low temperatures.